Does Transaction Isolation Level Have to be Reset After Read

Question

I am trying to dirty check a SQL Server table, but I am not sure whether or not the settings are saved to the table and will effect other reads, or automatically reset after the read. I would like the uncommitted flag to only be used each time the procedure is called, and not effect other reads to the table.

Case 1:

set transaction isolation level read uncommitted
select * from table

Case 2:

set transaction isolation level read uncommitted
select * from table
set transaction isolation level read committed

Is the last line in Case 2 necessary?